Female indris determine the rhythmic structure of the song and sustain a higher cost when the chorus size increases.

摘要: Among the behavioral traits shared by some nonhuman primate species and humans there is singing. Unfortunately, our understanding of animals' rhythmic abilities still in its infancy. Indris are only lemurs who sing live monogamous pairs, usually forming a group with their offspring. All adult members participate choruses that emitted regularly play role advertising territorial occupancy intergroup spacing. Males females emit phrases have similar frequency ranges but may differ temporal structure. We examined whether individuals' contribution to song change according chorus size, total duration or individual using inter-onset intervals within phrase between phrases. found structure indri's songs depends on factors different for males females. showed significantly higher variation rhythm that, changes size. Our findings indicate female indris sustain cost singing than when number singers increases. These results suggest cross-species investigations will be crucial evolutionary frame which such sexually dimorphic occurred.